It is well known in the aeronautical sciences that an aircraft capable of hover and/or of slow flight is typically not well-suited to long-distance efficient cruising flight. One drawback of aircraft capable of long-distance efficient cruising flight is that such aircraft typically require long runways to be utilized for take-off and landing. This becomes problematic when there is not sufficient space for the requisite runway, meaning that such aircraft may not be used.
Certain known or proposed aircraft launch, retrieval, or launch and retrieval systems and methods have attempted to solve these problems, but are each flawed in multiple manners. A first known or proposed aircraft launch and retrieval method employs a rotary wing aircraft to facilitate launch and retrieval of a fixed wing aircraft. To launch the fixed wing aircraft in the first known or proposed aircraft launch and retrieval method, the rotary wing aircraft is stiffly mated to the fixed wing aircraft via insertion of a plurality of balls mounted to the fixed wing aircraft into corresponding socket structures of the rotary wing aircraft. After mating, the rotary wing aircraft hoists the fixed wing aircraft, accelerates to a desired airspeed, and releases the fixed wing aircraft. To retrieve the fixed wing aircraft in the first known or proposed aircraft launch and retrieval method, this process is reversed—the rotary wing aircraft matches the airspeed of the fixed wing aircraft, stiffly mates with the fixed wing aircraft in midair, decelerates, and carries the fixed wing aircraft to a desired landing area.
This first known or proposed aircraft launch and retrieval method has numerous disadvantages. One disadvantage is that retrieving the fixed wing aircraft by stiffly mating the rotary wing aircraft to the fixed wing aircraft in midair is impractical in that it requires extreme precision and is unforgiving. Specifically, retrieval involves the rotary wing aircraft matching the fixed wing aircraft's airspeed, aligning each socket structure above its corresponding ball, and decreasing its altitude such that each socket structure receives and secures its corresponding ball. Even partial improper performance of one of these steps could result in retrieval failure, or worse: damage to either aircraft. Retrieval becomes even more complex in adverse weather conditions, such as rain or high winds, when aircraft movement becomes even more imprecise and unpredictable. Another disadvantage with this first known or proposed aircraft launch and retrieval method is that retrieving the fixed wing aircraft by stiffly mating the rotary wing aircraft to the fixed wing aircraft in midair is (relatively) high fuel costs—the operator must ensure that the rotary wing aircraft has enough fuel to chase the fixed wing aircraft to mate therewith. Launch using the first known or proposed aircraft launch and retrieval method is also problematic since imperfectly-synchronized release of the multiple connections can lead to destruction of both the rotary wing aircraft and the fixed wing aircraft.
A second known or proposed aircraft retrieval method employs a helicopter to facilitate retrieval of a fixed wing aircraft. To retrieve the fixed wing aircraft from wing-borne flight in the second known or proposed aircraft retrieval method, the helicopter hovers at a designated altitude while supporting a complex capture apparatus. In one proposed embodiment, this capture apparatus includes a horizontal beam from which a plurality of capture lines freely dangle (i.e., have one end connected to the horizontal beam and one free end). The helicopter is attached to a fixture, such as a vehicle, via an attachment line. The fixed wing aircraft is flown such that the fixed wing aircraft avoids the attachment line and contacts and captures one of the dangling capture lines.
This second known or proposed aircraft retrieval method has numerous disadvantages. One disadvantage due to the freely dangling capture lines is that the likelihood of capture is lower if the fixed wing aircraft contacts a capture line near its free end. For instance, if the fixed wing aircraft contacts a capture line near its free end, the capture line may simply bounce off of the fixed wing aircraft and upward, making capture impossible at this point. This minimizes the window within which the fixed wing aircraft may approach the helicopter for capture, increasing the difficulty of capture. Another disadvantage due to the freely dangling capture lines is that, after the fixed wing aircraft captures a capture line, the momentum of the fixed wing aircraft may cause the fixed wing aircraft to wrap-around the horizontal beam and contact the helicopter, with disastrous results. Another disadvantage is that the fixed wing aircraft must approach the helicopter in a direction that is substantially perpendicular to the horizontal beam. In other words, the fixed wing aircraft must approach the helicopter in one of only two directions—toward the front of the helicopter substantially perpendicularly to the beam or toward the rear of the helicopter substantially perpendicularly to the beam. Otherwise, the fixed wing aircraft would contact the attachment line during capture. Another disadvantage is that the fixed wing aircraft must avoid the attachment line while aiming for the capture lines, adding complexity to controlling the fixed wing aircraft during retrieval. Another disadvantage is that continued movement of the fixed wing aircraft after capture will violently jerk the helicopter a certain distance while the fixed wing aircraft is decelerating, which could damage the helicopter or the capture apparatus.
A third known or proposed aircraft retrieval method employs a kite, a balloon, or a crane and a tether to facilitate retrieval of a fixed wing aircraft. To retrieve the fixed wing aircraft from wing-borne flight in the third known or proposed aircraft retrieval method, the kite, balloon, or crane is used to suspend the tether between the kite, balloon, or crane and a fixture on the ground or a vehicle. The fixed wing aircraft is flown such that the fixed wing aircraft contacts and captures the tether.
This third known or proposed aircraft retrieval method has numerous disadvantages. One disadvantage when the third known or proposed aircraft retrieval method employs a kite or a balloon is that the kite or balloon cannot be maneuvered by the operator. The kite or balloon is thus vulnerable to poor weather conditions that could wreak havoc on the stability of the tether. For instance, high winds could cause location and/or altitude of the kite or balloon—and the location, altitude, and orientation of the tether suspended therefrom—to vary wildly, making it difficult to capture the tether with the fixed wing aircraft. One disadvantage when the third known or proposed aircraft retrieval method employs a kite is that, in most instances, the kite must be anchored to a moving vehicle (such as a boat at sea) to ensure that the kite remains airborne during retrieval. This makes land-based retrieval using the kite impractical at best and impossible at worst. One disadvantage when the third known or proposed aircraft retrieval method employs a crane that is expensive, heavy, and limits the flexibility of the third known or proposed aircraft retrieval method—it is difficult, time-consuming, and expensive to move a crane from one location to another to conduct retrievals in different places and also difficult to compactly stow a crane.
A fourth known or proposed aircraft retrieval method employs a helicopter to facilitate retrieval of a fixed wing aircraft. To retrieve the fixed wing aircraft from wing-borne flight in the fourth known or proposed aircraft launch and retrieval method, one end of a line is connected to a helicopter and a free end of the line dangles below the helicopter. The fixed wing aircraft is flown such that the fixed wing aircraft contacts and captures the line.
This fourth known or proposed aircraft retrieval method has numerous disadvantages. One disadvantage due to the freely dangling line is that the likelihood of capture is lower if the fixed wing aircraft contacts the line near its free end. For instance, if the fixed wing aircraft contacts the line near its free end, the line may simply bounce off of the fixed wing aircraft and upward, making capture impossible at this point. This minimizes the window within which the fixed wing aircraft may approach the helicopter for capture, increasing the difficulty of capture. Another disadvantage due to the freely dangling line is that, after the fixed wing aircraft captures the line, the momentum of the fixed wing aircraft may cause the fixed wing aircraft to wrap-around and contact the helicopter, with disastrous results. Another disadvantage is that continued movement of the fixed wing aircraft after capture will violently jerk the helicopter a certain distance while the fixed wing aircraft is decelerating, which could damage the helicopter.
There is a need for new systems and methods by which aircraft that otherwise require a long runway may be launched and retrieved from small spaces that solve these problems.